Shot cylinder controller for die casting machines and the like

Abstract

A shot cylinder controller for injection molding machines comprises a valve connected with one side of the shot cylinder and including a valve head which is movable with respect to a seat. The valve head is connected with at least two, lineally extensible actuators, interconnected in an end-to-end relationship. The actuators are independently extended and retracted, whereby selective manipulation of the actuators varies the position of the valve head, and thereby controls the extension of the shot cylinder and regulates the speed of die injection.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
       1. A molding machine having a die means in combination with a shot cylinder and a controller therefor, wherein: said shot cylinder comprises a housing having a shot piston mounted slidably therein for actuating a plunger for injecting a flowable material into said die, whereby translation of said shot piston in said housing controls the speed at which said die means associated with the die casting machine is injected with said flowable material;   said controller comprising: a valve connected with one side of said shot cylinder, and including a body having a fluid passageway therethrough, and throttling means disposed in said passageway for restricting the flow of fluid therethrough;   at least two, lineally extensible actuators interconnected in an end-to-end relationship, connected with said throttling means, and having means for independently extending and retracting each actuator, whereby selective manipulation of said actuators varies the position of said throttling means in said passageway and thereby controls extension of said shot piston, and thereby regulates the speed at which the flowable material is injected into said die means; and   said throttling means being disposed at a free end of a valve stem, whereby fluid exhausted from said shot cylinder impinges on said throttling means and automatically retracts said actuators.     
     
     
       2. A shot cylinder controller as set forth in claim 1, wherein: said actuators are binary, wherein each actuator has only a fully extended position and a fully retracted position, with no intermediate operational positions therebetween.   
     
     
       3. A shot cylinder controller as set forth in claim 2, wherein: each of said actuators have a different stroke length.   
     
     
       4. A shot cylinder controller as set forth in claim 3, wherein: said actuator stroke lengths are proportioned with respect to each other in a 1 2  sequence.   
     
     
       5. A shot cylinder controller as set forth in claim 4, wherein said actuators each comprise: a hydraulic cylinder having a piston telescoping in a housing valve means having a first position wherein pressurized fluid is introduced to a power side of said piston to extend the same, and a second position wherein the pressurized fluid is exhausted into a reservoir.   
     
     
       6. A shot cylinder controller as set forth in claim 5, wherein: said actuators are mounted in a substantial coaxial relationship.   
     
     
       7. A shot cylinder controller as set forth in claim 6, wherein: said throttling means is disposed generally axially in said passageway at a location upstream of said controller.   
     
     
       8. A shot cylinder controller as set forth in claim 7, wherein: said throttling means comprises a poppet-type valve having a seat in said housing and a valve head shaped for mating reception in said seat.   
     
     
       9. A shot cylinder controller as set forth in claim 8, wherein: said valve seat and said valve head are shaped so that opening said valve head a given distance from a previous open position results in a proportionate increase in fluid flow through said valve.   
     
     
       10. A shot cylinder controller as set forth in claim 1, wherein: each of said actuators has a different stroke length.   
     
     
       11. A shot cylinder controller as set forth in claim 10, wherein: said actuator stroke lengths are proportioned with respect to each other in a 1 2  sequence.   
     
     
       12. A shot cylinder controller as set forth in claim 1, wherein said actuators each comprise: a hydraulic cylinder having a piston telescoping in a housing valve means having a first position wherein pressurized fluid is introduced to a power side of said piston to extend the same, and a second position wherein the pressurized fluid is exhausted into a reservoir.   
     
     
       13. A shot cylinder controller as set forth in claim 1, wherein: said throttling means is disposed generally axially in said passageway at a location upstream of said controller.   
     
     
       14. A shot cylinder controller as set forth in claim 1, wherein: said throttling means comprises a poppet-type valve having a seat in said valve body and a valve head shaped for mating reception in said seat.   
     
     
       15. A shot controller as set forth in claim 14, wherein: said valve seat and said valve head are shaped so that opening said valve head a given distance from a previous open position results in a proportionate increase in fluid flow through said valve.   
     
     
       16. In a die casting machine having a hydraulic shot cylinder with an actuator rod connected with one side of a cylinder plunger which extends to inject molten metal into a die, the improvement of a control arrangement to control the injection into said die, comprising: a control valve, comprising: a valve body having a fluid passageway with an inlet and an outlet;   throttling means disposed in said passageway between said inlet and said outlet for restricting the flow of fluid through said passageway;   a valve controller connected with said throttling means and including at least two, lineally extensible actuators interconnected in an end-to-end relationship, and having means for independently extending and retracting each actuator, whereby selective manipulation of said actuators varies the position of said throttling means in said passageway and thereby controls fluid flow through said valve;   means for connecting said control valve with that end of said shot cylinder associated with the one side of said cylinder plunger, whereby hydraulic fluid exhausted from said shot cylinder during injection into said die flows through said control valve;   means for sensing the longitudinal position of said actuator rod with respect to said shot cylinder; and   means for automatically shifting said actuators in response to the location of said actuator rod.     
     
     
       17. A machine as set forth in claim 16, wherein: said actuators are binary, wherein each actuator has only a fully extended position and a fully retracted position, with no intermediate operational positions therebetween.   
     
     
       18. A machine as set forth in claim 17, wherein: each of said actuators has a different stroke length.   
     
     
       19. A machine as set forth in claim 18, wherein: said actuator stroke lengths are proportioned with respect to each other in a 1 2  sequence.   
     
     
       20. A machine as set forth in claim 19, wherein said actuators each comprise: a hydraulic cylinder having a piston telescoping in a housing, valve means having a first position wherein pressurized fluid is introduced to a power side of said piston to extend the same, and a second position wherein the pressurized fluid is exhausted to a reservoir, and means for retracting said piston.   
     
     
       21. A machine as set forth in claim 20, wherein said actuator extending and retracting means comprises: a four-way valve for each of said actuators;   a high-pressure manifold communicating opposite ends of said shot cylinder with a pair of check valves disposed adjacent each end of said manifold, whereby maximum pressure is maintained in said manifold;   conduits communicating said high pressure manifold with an inlet port of each four-way valve;   an exhaust manifold communicating with a fluid reservoir; and   conduits communicating said exhaust manifold with an outlet port of each four-way valve.   
     
     
       22. A machine as set forth in claim 21, wherein: said throttling means comprises a poppet-type valve having a seat in said housing and a valve head shaped for mating reception in said seat.   
     
     
       23. A machine as set forth in claim 22, wherein: said valve seat and said valve head are shaped so that opening said valve head a given distance from a previous open position results in a proportionate increase in die injection speed.   
     
     
       24. A controller for flow valves having a body with a fluid passageway therethrough, and throttling means disposed in said passageway for restricting the flow of fluid therethrough, said controller comprising: at least two, lineally extensible actuators interconnected in an end-to-end relationship, adapted for connection with said throttling means, and having means for independently extending and retracting each actuator, whereby selective manipulation of said actuators varies the position of said throttling means in said passageway and thereby controls fluid flow through said valve; each of said actuators having a generally cylindrically-shaped body closely and coaxially received in a mating bore portion of said valve body, and including a U-shaped cavity at one end of said actuator, and a cylindrical plunger at the other end of said actuator; said actuator plunger being insertable into and closely received in the U-shaped cavity of an adjacent one of said actuators to operably interconnect said actuators, and form a hydraulically operated actuator cylinder therebetween.   
     
     
       25. A valve controller as set forth in claim 24, wherein: said actuators are binary, wherein each actuator has only a fully extended position and a fully retracted position, with no intermediate operational positions therebetween.   
     
     
       26. A valve controller as set forth in claim 25, wherein: each of said actuators has a different stroke length.   
     
     
       27. A valve controller as set forth in claim 26, wherein: said actuator stroke lengths are proportioned with respect to each other in a 1 2  sequence.   
     
     
       28. A valve controller as set forth in claim 27, wherein: an upstreammost one of said actuators is adapted to carry said throttling means thereon; and   said throttling means includes a free surface with a portion thereof disposed in said passageway perpendicular to the translational axis of said actuators, whereby fluid pressure acting on said throttling means free surface provides said actuator retracting means.   
     
     
       29. A valve controller as set forth in claim 28, wherein: each U-shaped body cavity of said actuators is shaped to mate with a fluid port for pressurizing and exhausting said actuator cylinders.   
     
     
       30. A valve controller as set forth in claim 29, wherein: each actuator body includes a peripheral groove with a seal mounted therein to form a sliding seal with the valve body wall defining said mating bore.   
     
     
       31. A valve controller as set forth in claim 24, wherein: each of said actuators has a different stroke length.   
     
     
       32. An injection molding machine having a die and a hydraulic shot cylinder providing the motive force for injecting flowable material into said die, the improvement of a control valve means connected with one side of said shot cylinder for controlling extension of a ram portion of said shot cylinder, comprising: a valve body having a fluid passageway with an inlet and an outlet;   throttling means disposed in said passageway between said inlet and said outlet for restricting the flow of fluid through said passageway;   a valve controller connected with said throttling means and including at least two, lineally extensible actuators interconnected in an end-to-end relationship, and having means for independently extending and retracting each actuator, whereby selective manipulation of said actuator varies the position of said throttling means in said passageway and thereby controls fluid flow through said valve, and wherein   said valve means comprises: a four-way valve for each of said actuators;   a high-pressure manifold communicating with each side of said shot cylinder on either side of said shot piston with a pair of check valves disposed adjacent each end of said manifold, whereby maximum pressure is maintained in said manifold;   conduits communicating said high pressure manifold with an inlet port of each four-way valve;   an exhaust manifold communicating with a fluid reserovir; and   conduits communicating said exhaust manifold with an outlet port of each four-way valve.     
     
     
       33. A machine as set forth in claim 32, including: means for sensing the position of a rod portion of said shot cylinder; and   means for automatically shifting said four-way valves in response to the location of said shot rod.   
     
     
       34. A machine as set forth in claim 33, wherein: said throttling means comprises a poppet-type valve having a seat in said housing and a valve head shaped for mating reception in said seat.   
     
     
       35. A machine as set forth in claim 34, wherein: said valve seat and said valve head are shaped so that opening said valve head a given distance from a previous open position results in a proportionate increase in die injection speed.